Field
Embodiments of the present invention generally relate to apparatus and methods for processing substrate at high temperature. Particularly, embodiments of the present invention relate to apparatus and methods for supporting a substrate in a processing chamber operating at high temperatures.
Description of the Related Art
Electrostatic chucks are commonly used in supporting and securing a substrate in a processing chamber. An electrostatic chuck generally has a non-conductive body, such as a ceramic body, having an embedded DC electrode for generating chucking force. One or more heating element may be included in the substrate support to provide heating during processing. An RF electrode may be embedded inside a non-conductive body. The RF electrode delivers bias power to generate plasma while the DC electrode generates chucking force for securing a substrate thereon. A heater may be embedded in the non-conductive body to provide heating. A cooling base may be attached to non-conductive body to cool the non-conductive body. The heater and the cooling base work together to control the temperature of the electrostatic chuck and the substrate supported thereon.
Existing electrostatic chucks generally have metal clamping devices to secure the non-conductive body and the cooling base and use organic O-rings to provide sealing. However, the metal clamping devices and organic O-rings cannot function properly at elevated temperatures, such as at a temperature higher than 350° C. At 350° C., the operating temperature exceeds the performance limits for high temperature organic O-Rings. At elevated temperatures, metal clamping devices constrain thermal expansion of the non-conductive body and the cooling base. Additionally, metal clamping devices, generally made from refractory metal such as titanium, will also introduce metal contamination under processing chemistry.
Therefore, there is a need for electrostatic chuck for operating at elevated temperatures.